format long
w=0;
e=0;
r=0;
t=0;
q=0;
y=[0.3;0.4;0.5;0.6];
e=[0.5488;0.4493;0.3679;0.3012];
x=y-e;
w=y(1)*(q-x(2))*(q-x(3))*(q-x(4))/((x(1)-x(2))*(x(1)-x(3))*(x(1)-x(4)));
e=y(2)*(q-x(1))*(q-x(3))*(q-x(4))/((x(2)-x(1))*(x(2)-x(3))*(x(2)-x(4)));
r=y(3)*(q-x(1))*(q-x(2))*(q-x(4))/((x(3)-x(1))*(x(3)-x(2))*(x(3)-x(4)));
t=y(4)*(q-x(1))*(q-x(2))*(q-x(3))/((x(4)-x(1))*(x(4)-x(2))*(x(4)-x(3)));
ans=w+e+r+t